Low immunogenicity of LNP allows repeated administrations of CRISPR-Cas9 mRNA into skeletal muscle in mice

Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders.

KAJIAN ERGONOMI SARANA PENDUKUNG PROSES BELAJAR TERHADAP KELUHAN GOTRAK MAHASISWA INSTITUSI PENDIDIKAN X

ABSTRACT Quality of learning is determined by a classroom, where a classroom must have facilities to support the learning process, at least chairs, tables, blackboards, and LCD projectors. The design of supporting facilities for the learning process that is not following ergonomic principles can cause the risk of muscle and skeletal disorders. This study aims to examine and provide an overview related to ergonomic support facilities for the learning process contained in the classrooms of Educational Institution X. the learning process is not following the principles of ergonomics and causes complaints of skeletal muscle disorders in students. Complaints of muscle disorders felt by 97.61% of students in their body parts and related to choices when they study in the classroom, it is necessary to take corrective steps by redesigning to support the existing learning process and for students to have a comfortable seat so as not to display skeletal muscle disorders. Key word: ergonomic, study posture, MSDs ABSTRAK Kualitas pembelajaran yang baik dipengaruhi oleh karakteristik ruang kelas, dimana dalam sebuah ruang kelas harus memiliki sarana pendukung proses belajar minimal kursi, meja, papan tulis, dan LCD pyoyektor. Perancangan desain sarana pendukung proses belajar yang tidak sesuai prinsip ergonomi dapat menyebabkan risiko gangguan otot dan tulang rangka Penelitian ini bertujuan untuk mengkaji dan memberi gambaran terkait ergonomic sarana pendukung proses belajar yang terdapat pada ruang kelas Institusi Pendidikan X. Berdasarkan hasil penelitian diketahui bahwa desain sarana pendukung proses belajar tidak sesuai dengan prinsip ergonomi dan menyebabkan keluhan gangguan otot rangka pada mahasiswa. Keluhan gangguan otot rangka dirasakan oleh 97,61% mahasiswa pada bagian-bagian tubuhnya dan berhubungan bermakna dengan postur janggal pada saat mereka belajar di ruang kelas diperlukan adanya langkah perbaikan dengan mendesain ulang sarana pendukung proses belajar yang ada dan atau menyerukan kepada mahasiswa agar memilih tempat duduk yang nyaman agar tidak mengeluhkan gangguan otot rangka. Kata kunci: ergonomi, postur belajar, gotrak

Emerging role of MyomiRs as Biomarkers and Therapeutic Targets in Skeletal Muscle Diseases

Several chronic diseases lead to skeletal muscle loss and a decline in physical performance. MicroRNAs (miRNA) are small, non-coding RNAs, which has exhibited its role in the development and diseased state of the skeletal muscle. miRNA regulates gene expression by binding to the 3' untranslated region of its target mRNA. Due to the robust stability in biological fluids, miRNAs are ideal candidate as biomarker. These miRNAs provide a novel avenue in strengthening our awareness and knowledge about the factors governing skeletal muscle functions such as, development, growth, metabolism, differentiation and cell proliferation. It also helps in understanding the therapeutic strategies in improving or conserving skeletal muscle health. This review outlines the evidence regarding the present knowledge on the role miRNA as a potential biomarker in skeletal muscle diseases and their exploration might be a unique and potential therapeutic strategy for various skeletal muscle disorders.

Skeletal Muscle Mitochondria Dysfunction in Genetic Neuromuscular Disorders with Cardiac Phenotype

Mitochondrial dysfunction is considered the major contributor to skeletal muscle wasting in different conditions. Genetically determined neuromuscular disorders occur as a result of mutations in the structural proteins of striated muscle cells and therefore are often combined with cardiac phenotype, which most often manifests as a cardiomyopathy. The specific roles played by mitochondria and mitochondrial energetic metabolism in skeletal muscle under muscle-wasting conditions in cardiomyopathies have not yet been investigated in detail, and this aspect of genetic muscle diseases remains poorly characterized. This review will highlight dysregulation of mitochondrial representation and bioenergetics in specific skeletal muscle disorders caused by mutations that disrupt the structural and functional integrity of muscle cells.

Ion Channel Gene Mutations Causing Skeletal Muscle Disorders: Pathomechanisms and Opportunities for Therapy

Skeletal muscle ion channelopathies (SMICs) are a large heterogeneous group of rare genetic disorders caused by mutations in genes encoding ion channel subunits in the skeletal muscle mainly characterized by myotonia or periodic paralysis, potentially resulting in long-term disabilities. However, with the development of new molecular technologies, new genes and new phenotypes, including progressive myopathies, have been recently discovered, markedly increasing the complexity in the field. In this regard, new advances in SMICs show a less conventional role of ion channels in muscle cell division, proliferation, differentiation, and survival. Hence, SMICs represent an expanding and exciting field. Here, we review current knowledge of SMICs, with a description of their clinical phenotypes, cellular and molecular pathomechanisms, and available treatments.

Melatonin as a Potential Multitherapeutic Agent

Melatonin (N-acetyl-5-methoxytryptamine, MEL) is a hormone produced by the pineal gland that was discovered many years ago. The physiological roles of this hormone in the body are varied. The beneficial effects of MEL administration may be related to its influence on mitochondrial physiology. Mitochondrial dysfunction is considered an important factor in various physiological and pathological processes, such as the development of neurodegenerative and cardiovascular diseases, diabetes, various forms of liver disease, skeletal muscle disorders, and aging. Mitochondrial dysfunction induces an increase in the permeability of the inner membrane, which leads to the formation of a permeability transition pore (mPTP) in the mitochondria. The long-term administration of MEL has been shown to improve the functional state of mitochondria and inhibit the opening of the mPTP during aging. It is known that MEL is able to suppress the initiation, progression, angiogenesis, and metastasis of cancer as well as the sensitization of malignant cells to conventional chemotherapy and radiation therapy. This review summarizes the studies carried out by our group on the combined effect of MEL with chemotherapeutic agents (retinoic acid, cytarabine, and navitoclax) on the HL-60 cells used as a model of acute promyelocytic leukemia. Data on the effects of MEL on oxidative stress, aging, and heart failure are also reported.

The Role of Autophagy in Skeletal Muscle Diseases

Skeletal muscle is the most abundant type of tissue in human body, being involved in diverse activities and maintaining a finely tuned metabolic balance. Autophagy, characterized by the autophagosome–lysosome system with the involvement of evolutionarily conserved autophagy-related genes, is an important catabolic process and plays an essential role in energy generation and consumption, as well as substance turnover processes in skeletal muscles. Autophagy in skeletal muscles is finely tuned under the tight regulation of diverse signaling pathways, and the autophagy pathway has cross-talk with other pathways to form feedback loops under physiological conditions and metabolic stress. Altered autophagy activity characterized by either increased formation of autophagosomes or inhibition of lysosome-autophagosome fusion can lead to pathological cascades, and mutations in autophagy genes and deregulation of autophagy pathways have been identified as one of the major causes for a variety of skeleton muscle disorders. The advancement of multi-omics techniques enables further understanding of the molecular and biochemical mechanisms underlying the role of autophagy in skeletal muscle disorders, which may yield novel therapeutic targets for these disorders.

Adiponectin and Its Mimics on Skeletal Muscle: Insulin Sensitizers, Fat Burners, Exercise Mimickers, Muscling Pills … or Everything Together?

Adiponectin (ApN) is a hormone abundantly secreted by adipocytes and it is known to be tightly linked to the metabolic syndrome. It promotes insulin-sensitizing, fat-burning, and anti-atherosclerotic actions, thereby effectively counteracting several metabolic disorders, including type 2 diabetes, obesity, and cardiovascular diseases. ApN is also known today to possess powerful anti-inflammatory/oxidative and pro-myogenic effects on skeletal muscles exposed to acute or chronic inflammation and injury, mainly through AdipoR1 (ApN specific muscle receptor) and AMP-activated protein kinase (AMPK) pathway, but also via T-cadherin. In this review, we will report all the beneficial and protective properties that ApN can exert, specifically on the skeletal muscle as a target tissue. We will highlight its effects and mechanisms of action, first in healthy skeletal muscle including exercised muscle, and second in diseased muscle from a variety of pathological conditions. In the end, we will go over some of AdipoRs agonists that can be easily produced and administered, and which can greatly mimic ApN. These interesting and newly identified molecules could pave the way towards future therapeutic approaches to potentially prevent or combat not only skeletal muscle disorders but also a plethora of other diseases with sterile inflammation or metabolic dysfunction.